A servo motor is an engine that accurately controls the operation of mechanical components in a servo system. As an indirect variable speed device for auxiliary motors, its core function is to convert electrical signals into accurate mechanical motion, meeting the high-precision control requirements for speed, position, and torque.
The servo motor achieves high-precision positioning through a closed-loop control system. Its working principle mainly relies on pulse signals: for every pulse received by the motor, it rotates by a corresponding angle to achieve displacement; At the same time, for each angle of rotation of the motor, a corresponding number of pulses are emitted, which echo the received pulses. The system accurately controls the motor rotation by comparing the number of pulses emitted and feedback pulses.
Servo motors are mainly divided into two categories: DC servo motors and AC servo motors:
DC servo motor: simple structure, easy control, but there are issues with brush and commutator wear, resulting in high maintenance costs.
Communication servo motor: brushless and commutator, reliable operation, simple maintenance. Its principle is the same as that of a two-phase asynchronous motor, with two windings installed on the stator - the excitation winding and the control winding. By appropriately selecting the capacitance size, the phase difference of the current passing through the two windings is made close to 90 °, generating a rotating magnetic field and driving the rotor to rotate.
Servo motors have the following characteristics:
High precision: Accurate control of speed and position is achieved through a closed-loop control system.
Quick response: The rotor speed is controlled by input signals and can respond quickly to meet dynamic control requirements.
Small electromechanical time constant: The motor starts and stops quickly, with good dynamic performance.
High linearity: The motor output is linearly related to the input signal, making it easy to control.
No self rotation phenomenon: When the signal voltage is zero, the motor immediately stops rotating to avoid losing control.
classification
According to the type of current, it can be divided into AC servo motors and DC servo motors. AC servo motor is the main type, with a wide power range and strong anti-interference ability; DC servo motors have a simple structure and are suitable for small equipment, but require regular replacement of carbon brushes.
According to application scenarios, it can be divided into universal type, high-precision type, explosion-proof/waterproof type, etc. Universal type suitable for standard industrial scenarios; High precision type is used in scenarios such as semiconductor manufacturing that require high positioning accuracy; Explosion proof/waterproof type is suitable for special environments such as chemical and underwater operations.
According to mechanical structure, it can be divided into rotary servo motors and linear servo motors. Rotary servo motors are commonly used for angle control, while linear servo motors can directly output linear motion without the need for a transmission mechanism.